This invention relates to data communication systems of the type using photocouplers.
In known data communication systems, the use of couplers is essential for coupling transmitters and receivers to communication lines, and such couplers are usually transformers. In practice, transformer couplers are generally costly and often require modifications in construction and dimensions depending upon the signal transmission rate of the communication system. Recently, with marked improvement in the quality of photocoupler, an increasing number of them have replaced transformer couplers. Advantageously, photocouplers can be manufactured at low cost and are small in size and operable over a wide range of signal transmission without the need for modifying their construction and dimensions. Therefore, by using photocouplers, the cost of a data communication system can be reduced.